Pneumatic tool.



iA. M.. ROBERTS & E. G. WLLJAMSON.

PNEUMATIC TOOL.

APPLicATxoN min sPT.1,1917.

Patente May 28, 1918.

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Speeiestion of Letters Patent.

TGL.

Patented Msgr dppliuation filed September i', 131'?. Serial 1t o. M9334.

new and useful lmprovementsin Pneumatic A Tools. of which the :following is e. specificstion.

T his invention relates to improvements in pneumatic tools, and is especially adaptable for tools for cutting rivet heads and in other operations requiring the use of the cold chisel.` Our invention has for itsobjeot to provide e safe and convenient tool for this purpose and in particular an improved valve for devices of this kind.

The invention comprises a cylinder provided at one end with a tool of the kind desired and 'having e reciprocating air valve at the opposite end connected with o. suitable source of compressed air. A hernrner in the form of a piston is slidable in the vcylinder to impart blows to the tool. Passages are provided for admitting air from the source of supply to either end rof the cylinder by the reciproeation of the valve, which is operated by means of a lever and connecting linlr secured to the valve ond of the Cylinder, the valve having passages out therein for establishing proper communication between the source of air supply end Athe cylinder. By rocking the lever the valve may be moved to e'eet the reciprocetion of the piston in the cylinder. Refe'rrimlr to thc accompanying drawings,

Figure 1 is an elevation of our tool showing certain ports broken away to-show the lsir passsges. p

Fig. 2 is e section on line 2-2 ot Fig. l, showing rthe piston in position to deliver o blow, and the valve in position to admit oir to the lower end of the4 cylinder.

Figa S is section. similar to Fig. 2, showing the piston in striking position and the 'valve in position to admit air to the oppo sit/e end or' the eylinder. l

Fig, el is e cross section of the valve.

ln the drawings, 1 is o cylinder havin@ o.

- bnsliin 2 threaded to one end the buslnn being provided with n. threaded portion 3, to Wirioli is screwed e sleeve l formed with e. oliainber 4 therein. Slidable Within the cylinder 1 is piston or hummer 5. The

I slienir S of e tool i slidably mounted in the burning 2 and the sleeve l normally proes. reis.

jects into the cylinder 1, es shown in Fig'.

That portion of the shank of the tool Within v the chamber il is provided with a iiange 8 i iorznzng a stop which linnts movement et the tool relatively to the cylinder. This stop4 prevents the tool from being egectedslionld the piston be driven against its shank when. i

it is not being firmly held egoinstthe Work during the cutting operation. We also provide the chamber 4 with a. oo'nopressible`v i,

boiling device Qpreferably of e non-metallic substance, as rubber hose, adapted to be en-fV i i gegedby the ilange 8 when the tool is being driven forward. Otherineans can rbe used r* but, We

'for this purpose, such as a spring, find that a. non-metallic substance offerslitoil tie resistance to the tool and reducesvibraa tion and noise and gives a more desirous i bnng' act-ion. After the tool lhas kbeen driven forward by the impact of the piston, itis returned to normal position by the pressure .of the tool against the Work.

Air under pressure is admitted alternately to .opposite ends of the cylinder 1, to'drive the piston back and forth in the cylinder toL deliver e series of successive blowsto thetool. We accomplish this by providing the f end of the cylinder opposite the tool with a head in the form of a casing 10 having-e.kv valve chamber 11 therein, and having oppositely disposed inlet and outlet pipes 12 and 13, respectively, which serve also as handles To permit the inlet of air i,

for the device. from the inlet pipe to the valve chamber 1l there is provided a, passage 14 onda port-15.

sex! l Comunication is established between the 'Y valve chamber and one end of the cylinder 1 through passage 16, While it is established between the valve chamber andthe opposite end of the cylinder by means of port 17 (see Fig. l) connecting with pipe 18 leading to the other end of the cylinder et 19. Exhaust port 20 permits air to escape from the valve chamber 11 to exhaust pipe 13.' An opening 21 near the tool end of the cylinder permits air to escape therefrom.

Passage of sir through the various ports is controlled by means of a slide valve or plug 22 in valve ohamber 11 having a passage 23 extending diemetrioally therethrough near one end or" the plug, suoh passage communicating with a passage 24 at right angles to passage 23 (see Fig. 4). Passage 23 is adapted to register with inlet port 15 and with exhaust port 20 during {lider-ent stages of operation, while passage Qiegisteis with the eylincle eomninnioeing port 16. Toperinirb the passage of sii from inlet post 15 to port 1?, piovicle s groove E25 on the circumference of he valve, the groove having e right angular eontinuetion 26 which is adapted to regisei with port 17.

lllhe enel of the Valve chamber 11 is provided with a bushing 27 through which passes e rod 28 secured 'to velveplng enel. to the projecting encloi which is pivoecl e level` 9,9 uleiunied to a. link 30 connected lo support 231 secured to the easing 10. By rocking lever 29 the valve plug i9 may be ieoipi'oeated in J[he vlve chamber.

Assuming the valve to oe in the pc-sis' shown in Fig. 2, :iii1 passes from inler pipe 12 along passage-14, through port 15 into groove 25 on valve plug 22, around the groove to poi-t 17 and then through pipe 18 and -poi't 19 Where it enters the cylinder "so effect the return oi' the piston to position ready for a working blow. V17 ith thepiston in this position air within the eylinde Will hold the piston in the position shown., while excess air escapes through pori; 21. "/llhen ii: is desired to deliver a blow to the tool, the operator throws the lever 29 oiweifl, moin ing valve plug 22 to the position shown izo. Fig. 3, when the air will pass clown passage 23 and along passage 24 into the pori; 16 and thence into the cylinder, driving lie pissen to the end of the cylinder es shown in `Fig.. 3. The operato1 may 4then return the pieton to the valve end of the cjlinder by rocking lever 29 backward to the position Ashown in Vlllig. 2, when air will again pass along lie pipe 18 into the Cylinder at 19. By lie escape of part oi the .air through posi; 21 the piston is prevented from being resnined. foi'oibly to the valve enel of. the eylindei.

'Port- 21 also serves lo prevent compression in she lower encl of the eylincler lie piston 1s moving forwarcl to stifilze lilo??E Coinpieesi i dei: by esoepe pori Il@ in A shi'ough i in Valve 'to eflieust nono e o i; pipe 13, im norneliy eueneiiee'ly helcl ie-tive shown in Figi 2,

ioniIl 1 of *lle :li-ees ills-t should ii ecei' n he nieve-rl to opeieive position es shown in D .heck pressuie in' the cylincle: `Wonlfl by ly the force of the elo the niovemen of ne inireiiion: A i oo conipismg e cylinder Wiih seidl bool slidelile in'seicl e` linee?, e yjffeeigiocelele veli/e connected with i' en supply et the opposite enel tion, passages controlled ley saicl n seid hemmen, and ineens ooneollefl le eil pressue from seid senses o supply 'oz normally holding' the we in i opeeftive loosiiiom eyinflei', e le' es pivoted to Seidly one encl with e, tool, e, hammer 

